(CNN) — Think back to when you were a kid and movement was instinctive — and often infused with pure joy. Maybe it was racing your sister and dad to the front door. Or jumping on the bed with friends ...

It’s no secret that exercise, even in small doses, can improve your mood. Researchers even have a name for it: the feel-better effect. And while any physical activity — a walk, a swim, a bit of yoga — ...